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The sequence of an 11.1 kb fragment on the left arm of Saccharomyces cerevisiae chromosome VII reveals six open reading frames including NSP49, KEM1 and four putative new genes.

We report the sequence of an 11.1 kb fragment located on the left arm of chromosome VII of Saccharomyces cerevisiae. By sequence analysis we have detected six open reading frames (ORFs) longer that 300 bp, which cover 87% of the entire sequence. ORF G1645 is 100% identical to the KEM1 gene, also identified as DST2, XRN1, SEP1 and RAR5, while G1648 is 100% identical to the NSP49 or NUP49 gene. ORF G1642 shares some identity with a hypothetical protein of Caenorhabditis elegans, while the other four ORFs show no significant homology to known proteins.

Amino Acid Sequence↗

Polyamine regulation of ribosome pausing at the upstream open reading frame of S-adenosylmethionine decarboxylase.

Synthesis of S-adenosylmethionine decarboxylase (AdoMetDC), a key regulated enzyme in the pathway of polyamine biosynthesis, is feedback-controlled at the level of translation by spermidine and spermine. The peptide product of an upstream open reading frame (uORF) in the mRNA is solely responsible for polyamine regulation of AdoMetDC translation. Using a primer extension inhibition assay and in vitro protein synthesis reactions, we found ribosomes paused at or close to the termination codon of the uORF. This pause was greatly diminished with the altered uORFs' sequences that abolish uORF regulation in vivo. The half-life of the ribosome pause was related to the concentration of polyamines present but was unaffected by magnesium concentration. Furthermore, inhibition of translation initiation at a reporter gene placed downstream of the AdoMetDC uORF directly correlated with the stability of the ribosome pause at the uORF. These observations are consistent with a model in which regulation of ribosome pausing at the uORF by polyamines controls ribosome access to the downstream AdoMetDC reading frame.

Adenosylmethionine Decarboxylase↗

Five open reading frames upstream of the dnaK gene of E. coli.

The nucleotide sequence of 3.17 kb of DNA upstream of the dnaK gene of E. coli was determined. Analysis of the sequence indicated the presence of five open reading frames (ORFs), two of which are coded on one strand and three on the other. ORFs 3 and 4 appear to constitute an operon. One of the ORFs (htgA) is preceded by a -10 promoter sequence which is identical to that of the dnaK sigma 32 P1 promoter, and thus suggests that htgA could be a heat-shock gene. ORF4 and htgA overlap each other on opposite strands of DNA, this would offer some interesting regulatory possibilities.

Amino Acid Sequence↗

The simian immunodeficiency virus envelope open reading frame located after the termination codon is expressed in vivo in infected animals.

Genetic comparison of SIVmac to the human retroviruses generally associated with AIDS revealed a closer relationship to HIV-2 than to HIV-1. A common feature differentiating SIV and HIV-2 from HIV-1 is the size of the transmembrane portion of the envelope, which is smaller (gp32) in SIVmac and HIV-2 than in HIV-1 (gp41). The presence of this truncated form of the transmembrane glycoprotein in SIVmac and HIV-2 virions is apparently related to the presence of a translation termination codon in the env gene of all SIV proviruses analyzed as well as in one HIV-2 provirus. Since the carboxy terminus of the envelope transmembrane protein has been implicated in the cytopathic effect of HIV-1 in vitro, we decided to investigate whether putative expression of the open reading frame located after the termination codon correlates with the pathogenicity of SIVmac in vivo. We generated two synthetic peptides from the inferred amino acid sequence of SIVmac and tested their reactivity by Western blot against the sera of naturally and experimentally infected monkeys as well as against sera of HIV-2-infected individuals. Our results indicate that the protein synthesized from this open reading frame is expressed in vivo, since an immunoresponse can be detected against the synthetic peptides in two of three experimentally SIVmac-infected animals. However, no correlation can be found between its expression and disease progression at this time. Furthermore, a rabbit immune serum raised against the synthetic peptide failed to identify any specific protein in SIVmac-infected cells.

Amino Acid Sequence↗

Open reading frames flanking the peptidyl-tRNA hydrolase-encoding gene of Escherichia coli.

The nucleotide (nt) sequences flanking the peptidyl-tRNA hydrolase-encoding gene (pth) of Escherichia coli were determined and analyzed. A coding open reading frame (ORF-3), identified just downstream from pth, had a deduced amino acid (aa) sequence homologous to a family of GTP-binding proteins. We found discrepancies between the ORF-3 sequence from a plasmid clone used in previous studies and another one derived from Kohara's phage collection. Two putative genes, ORF-4 and ORF-2, were also found upstream from pth. ORF-4 could code for a 393-aa peptide homologous to membrane-bound proteins. The nt sequence between ORF-2 and pth revealed the existence of a CAP-binding site correctly positioned to regulate the expression of ORF-2.

Amino Acid Sequence↗

Characterization of a nondeleterious L1 insertion in an intron of the human factor VIII gene and further evidence of open reading frames in functional L1 elements.

We have characterized an insertional event in IVS-10 of the factor VIII gene in a pedigree containing a hemophilia A patient (JH-25). The inserted DNA is a 5' truncated L1 element that is 681 bp long followed by a 3'66-bp poly(A) tract. The L1 element is inserted 154 bp 5' to the start of exon 11 and is flanked by a 13- to 17-bp target site duplication. The L1 insertion is present in four generations of the patient's family. The maternal grandfather who carries the insertion does not have hemophilia A, indicating that the insertion is not the cause of hemophilia A in the patient. We have sequenced this insertion and two previously reported de novo L1 insertions in the factor VIII gene in patients JH-27 (3785 bp) and JH-28 (2132 bp). The three nucleotide sequences differ by 0.2-0.8%. All three of these L1 insertions have open reading frames (ORFs) (1192, 642, and 157 aa) and the three derived amino acid sequences are 98-99% identical. The previously reported sequence similarity between L1 3' ORFs and the polymerase domain of reverse transcriptases is maintained in the ORFs of the JH-27 and JH-28 L1 insertions. The presence of open reading frames and the close sequence similarity of these recently inserted L1 elements provide indirect evidence for the existence of a set of functional L1 elements that encode one or more proteins necessary for their retrotransposition.

Base Sequence↗

Expression of the human papillomavirus type 18 E7 gene by a cassette-vector system for the transcription and translation of open reading frames in eukaryotic cells.

We have constructed and functionally tested a cassette-vector-system for the transcription and translation of open reading frames (ORFs) in cells of higher eukaryotes. The vectors are derived from the plasmid pBR322 and can be selected and amplified in Escherichia coli. Alternative eukaryotic promoters can be inserted between the restriction sites SphI and KpnI, translation initiation motifs between KpnI and BglII, linkers for the adjustment of the translation reading frame and the insertion of genes or gene segments between BglII and HindIII, followed by a HindIII-EcoRI segment with splicing and polyadenylation signals derived from SV40. A prototype vector system, pORFEX11, 12 and 13, contains the strong cytomegalovirus immediately early promoter and a 10-bp motif of the SV40 T-antigen translation start. Polylinkers derived from pUC18 permit the insertion of ATG-less ORFs downstream from the ATG of the vector. Either of the three alternative polylinkers adjusts the appropriate translation frame. A similar construct contains the regulatable promoter of the Drosophila heat shock gene 70. We inserted genes or gene segments, that code for the bacterial chloramphenicol acetyltransferase, the bacterial gene conferring resistance against hygromycin, and the ORF E7 of the human papillomavirus type 18 into these vectors. After transfection of mouse L fibroblasts, all proteins and functions were expressed in accordance with the prediction. In transiently transfected L cells, the E7 protein expressed from pORFEX12 constitutes approximately 2.0% of total cell protein. This E7 protein could be localized by immunocytochemistry as a cytoplasmic component.

Amino Acid Sequence↗

The rIIA gene of bacteriophage T4. I. Its DNA sequence and discovery of a new open reading frame between genes 60 and rIIA.

We have determined the DNA sequence of the rIIA gene and have discovered a small open reading frame, rIIA.1, between genes 60 and rIIA. The predicted molecular weights of these proteins are 82,840 for rIIA and 8,124 for rIIA.1. The rIIA protein has a repeated motif which suggests that the gene has evolved by duplication. It also has a motif which suggests that it belongs to a group of ompR-like proteins that control regulation of gene expression in response to changes in the external environment. We have sequenced three different missense mutants whose mutations lie in the Ala segment of the rIIA genetic map. All three changes are found within the first 35 bp of the rIIA coding sequence. The region of control of protein synthesis is identical in the rIIA gene and in gene 44 of T4. We relate this finding to the high sensitivity of both RNAs to translational repression by the T4 regA gene product.

Amino Acid Sequence↗

Genes within genes: independent expression of phage T4 intron open reading frames and the genes in which they reside.

The td, nrdB, and sunY introns of bacteriophage T4 each contain a long open reading frame (ORF). These ORFs are preceded by functional T4 late promoters and, in the case of the nrdB intron ORF, a functional middle promoter. Expression of phage-encoded intron ORF-lacZ fusions indicates that these T4 genes are highly regulated. The lack of translation of these ORFs from early pre-mRNAs can be accounted for by the presence of secondary structures that are absent from the late RNAs. Because translation of the intron ORFs could disrupt core structural elements required for pre-mRNA splicing, such regulation may be necessary to allow expression of the genes in which they reside.

Cloning, Molecular↗

Mercury resistance in Bacillus cereus RC607: transcriptional organization and two new open reading frames.

The chromosomal mercury resistance determinant of Bacillus cereus RC607 confers resistance to inorganic mercury and to organomercurials. The order of genes in the completed mercury resistance determinant is operator-promoter 1 (O/P1) merR1 merT open reading frame 3 (ORF3) ORF4 merA O/P2 merR2 merB2 merB1. The previously undetermined 1-kb DNA sequence between the merA and merB1 genes includes two significant ORFs, whose predicted protein products are homologous with MerR (the transcriptional regulator) and MerB (the organomercurial lyase enzyme). Two transcriptional start sites (promoters), O/P1 at the beginning of the determinant and O/P2 immediately upstream of the sixth ORF, the newly identified merR2, were mapped by reverse transcriptase (RT) primer extension. A long 6.3-kb mRNA traversing all eight ORFs was shown by RT-PCR. Growth sensitivity measurements in liquid media and cellular mercury volatization assays characterized inducibility and differences in functional activity in B. cereus RC607 and after cloning of the mer determinant into plasmids in Escherichia coli.

Amino Acid Sequence↗

Open reading frame 73 is required for herpesvirus saimiri A11-S4 episomal persistence.

Herpesvirus saimiri (HVS) establishes a latent infection in which the viral genome persists as a non-integrated episome. Analysis has shown that only open reading frames (ORFs) 71-73 are transcribed in an in vitro model of HVS latency. ORF73 also colocalizes with HVS genomic DNA on host mitotic chromosomes and maintains the stability of HVS terminal-repeat-containing plasmids. However, it is not known whether ORF73 is the only HVS-encoded protein required for episomal maintenance. In this study, the elements required for episomal maintenance in the context of a full-length HVS genome were examined by mutational analysis. A recombinant virus, HVS-BAC delta71-73, lacking the latency-associated genes was unable to persist in a dividing cell population. However, retrofitting an ORF73 expression cassette into the recombinant virus rescued episomal maintenance. This indicates that ORF73 is the key trans-acting factor for episomal persistence and efficient establishment of a latent infection.

Antigens, Viral↗

The proteome of the bacterium Mycoplasma pneumoniae: comparing predicted open reading frames to identified gene products.

An existing proteome map of the bacterium Mycoplasma pneumoniae comprising proteins from 224 genes was extended to 305 genes. This corresponds to about 44% of the 688 proposed genome sequence derived open reading frames (ORFs). The newly assigned gene products were enriched, separated by one-dimensional or two-dimensional (2-D) gel electrophoresis and identified by mass spectrometry. The enrichment procedures included differential centrifugation, anion and cation exchange chromatography, affinity chromatography with heparin as a ligand and isolation of biotinylated proteins by binding to immobilized streptavidin. A comparative analysis of the identified proteins from 305 genes with the as yet unverified 383 ORFs concerning isoelectric point, molecular weight and number of transmembrane segments revealed that proteins with more than three predicted transmembrane segments and an isoelectric point above 10.5 are most likely not to be separated by 2-D gel electrophoresis. The mutual benefits of genomics and proteomics were shown by the identification of a todate unannotated 128 amino acid long protein.

Amino Acid Sequence↗

Mining the human genome using microarrays of open reading frames.

To test the hypothesis that the human genome project will uncover many genes not previously discovered by sequencing of expressed sequence tags (ESTs), we designed and produced a set of microarrays using probes based on open reading frames (ORFs) in 350 Mb of finished and draft human sequence. Our approach aims to identify all genes directly from genomic sequence by querying gene expression. We analysed genomic sequence with a suite of ORF prediction programs, selected approximately one ORF per gene, amplified the ORFs from genomic DNA and arrayed the amplicons onto treated glass slides. Of the first 10,000 arrayed ORFs, 31% are completely novel and 29% are similar, but not identical, to sequences in public databases. Approximately one-half of these are expressed in the tissues we queried by microarray. Subsequent verification by other techniques confirmed expression of several of the novel genes. Expressed sequence tags (ESTs) have yielded vast amounts of data, but our results indicate that many genes in the human genome will only be found by genomic sequencing.

Cell Line↗

Molecular characterization of Theileria orientalis piroplasm protein encoded by an open reading frame (To ORF2) in a genomic fragment.

In the present study, a novel antigenic protein expressed in the piroplasm stage of Theileria orientalis was characterized. A 4,707 bp genomic fragment amplified by PCR contained two open reading frames (ORFs). The deduced amino acid sequence of the first ORF showed significantly high similarlity to the ubiquitin carboxy terminal hydrolases/proteases while the second ORF (To ORF2) showed homology to several surface antigens of plasmodia. To ORF2 was expressed to determine whether the protein product is expressed by the parasite. In western blot analysis, bovine antiserum from a T. orientalis-infected calf recognized the recombinant protein containing a C-terminal part of the ORF expressed by baculovirus system. Western blot analysis with the anti-To ORF2 mouse serum recognized a 48 kDa protein in T. orientalis piroplasm lysates. Indirect immunofluorescence antibody test by confocal scanning laser microscopic analysis showed that antisera against the recombinant protein recognized T. orientalis piroplasm in the infected erythrocyte. The results from this study indicate that To ORF2 protein is expressed at the piroplasm stage and is immunogenic. This novel antigenic To ORF2 protein could be exploited for vaccine development against bovine piroplasmosis.

Amino Acid Sequence↗

RPS4-mediated disease resistance requires the combined presence of RPS4 transcripts with full-length and truncated open reading frames.

Arabidopsis RPS4 belongs to the Toll/interleukin-1 receptor (TIR)-nucleotide binding site (NBS)-Leu-rich repeat (LRR) class of disease resistance (R) genes. Like other family members in different plant species, RPS4 produces alternative transcripts with truncated open reading frames. The dominant alternative RPS4 transcripts are generated by retention of intron 3 or introns 2 and 3, which contain in-frame stop codons and lie downstream of the NBS-encoding exon. We analyzed the biological significance of these alternative transcripts in disease resistance by removing introns 2 and 3, either individually or in combination, from a functional RPS4-Ler (Landsberg erecta) transgene. Removal of one or both introns abolished the function of the RPS4 transgene, whereas expression was not affected. In addition, a truncated RPS4-Ler transgene encoding the putative TIR and NBS domains was not sufficient to confer resistance, suggesting that the combined presence of regular and alternative RPS4 transcripts is necessary for function. Interestingly, we observed partial resistance in transgenic lines expressing both intron-deficient and truncated transgenes. This finding confirms the requirement for regular and alternative RPS4 transcripts and indicates that alternative transcripts function at the protein level rather than as regulatory RNAs. Together with published results on the tobacco N gene, our data suggest that the generation of alternative TIR-NBS-LRR R gene transcripts is of general biological significance across plant species.

Arabidopsis↗

Expression of tobacco necrosis virus open reading frames 1 and 2 is sufficient for the replication of satellite tobacco necrosis virus.

Tobacco necrosis virus (TNV) is a small icosahedral plant virus which is often associated with satellite viruses. The genomic RNA of TNV contains six open reading frames (ORFs), of which ORFs 1 and 2 are thought to encode the viral polymerase. We demonstrate that tobacco protoplasts transfected with a vector containing TNV ORFs 1 and 2 under the control of the cauliflower mosaic virus 35S promoter, as well as protoplasts derived from transgenic Nicotiana tabacum containing the same gene(s), support replication of satellite tobacco necrosis virus RNA.

DNA-Directed RNA Polymerases↗

Hidden proteins encoded by non-canonical open reading frames: A review.

There is increasing evidence that translation is not limited to annotated protein-coding genes. Ribosome profiling sequencing, mass spectrometry-based proteomics, and immunopeptidomics have identified the productive translation of non-canonical open reading frames (ORFs). This suggests that the functional proteome includes not only conserved proteins but also proteins hidden in non-coding RNAs and de novo proteins. Some of these translated products are functional peptides, while others may be non-functional, potentially arising from evolutionary events. Several non-canonical ORF-encoded peptides have been found to regulate multiple physiological and pathological functions, particularly in cancer, immunity, and inflammation, indicating that they have potential as biomarkers and novel therapeutic targets. To better understand the diversity of functional peptides and translated non-canonical ORFs based on existing data, we summarize their classification according to transcriptional features and supporting evidence, including non-canonical ORFs located in ncRNAs and canonical mRNAs. This review provides a concise summary of the origin, discovery methods, and classification of non-canonical ORFs. It offers insights into the origins and functions of non-canonical ORF-encoded peptides from an evolutionary perspective, while also exploring the biological functions and regulatory mechanisms of these non-canonical ORF-encoded hidden proteins in tumorigenesis and progression.

Open Reading Frames↗